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MG MGB Technical - Cylinder marks
I have taken the head off and started to stip and inspect the engine to try to get an idea of its condition. The cylinder bores do not have a lip so hopefully not too much wear since it was last rebuilt.( I dont know its history other than it is a goldseal which may have been rebuilt since the original goldseal rebuild). Cylinder 3 has a scorch type mark on both the left and right sides, see pic. What would cause this is it something to be overly concerned about?
|If those marks are blue/purple, on steel that indicates in excess of 280 degC. I think Gold Seals were fitted with liners. Is there a corresponding hot spot on 2 or 4?|
|There appears to be a liner. Look at 6 oclock and you will see what appears to be a liner mark.|
|Thanks for the replys. I will hopefully get chance to have another look tomorrow but I dont remember see it in any of the other cylinders.|
Was lining of the cylinders a successful repair or did it bring its own problems?
|Putting a liner in returned the bores to original diameter which allowed the use of stock pistons and rings at the factory, a boring machine set up to a standard size and obviated the possible dangers of over boring. Putting a liner in is an excellent "repair".|
I have had another look and the marks are only in number 3. They do not appear to be blue or purple, more of a darker grey.
I have just done a drip down test as per John Twist. No 3 drained away quite quickly in comparison to the others so I am planning to take the pistons out to examine the piston rings as sell as the condition of the bearings.
|18V engine block production shifted to Qualcast in Leeds around 1971, there were problems with porosities on a lot of blocks. Rather than throw them away BL turned them into Goldseal units by fitting liners. A bargain giving a customer a new block not reconditioned!|
|Peter Burgess Tuning|
|Peter, Is that the same Qualcast as in Qualcast Lawn mowers?|
|I think so :) We had a customer many years ago who did the boring on the new blocks and he spilled the beans (pun intended).|
|Peter Burgess Tuning|
|Not so "QUALity CASTing then!!|
This thread was discussed between 26/08/2017 and 29/08/2017
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